The present invention relates to a hollow plastic bottle with an improved base.
Hollow plastic bottles generally include a recessed or inwardly extending or reentrant base structure. This type of base has been found to have good resistance to deformation, especially deformation caused by the effects of internal pressure.
However, it is desirable to provide a recessed base structure for hollow plastic bottles with improved strength properties. For example, increased strength properties in the recessed base will facilitate use of the container for increased heat applications, as pasteurization. Also, increased strength properties will improve impact strength, minimizing damage when the bottles are accidentally dropped. Further, improved strength properties in the base will help prevent roll-out, i.e., under pressure or heat the plastic bottles tend to roll-out or bulge at the base.
It is, therefore, a principal object of the present invention to provide a hollow plastic bottle with an improved base.
It is a further object of the present invention to provide an improved plastic bottle as aforesaid with improved strength properties in the base.
It is a still further object of the present invention to provide an improved plastic bottle as aforesaid which is easy to prepare and which is aesthetically pleasing.
Further objects and advantages of the present invention will appear hereinbelow.
It has now been found that the foregoing objects and advantages are readily obtained in accordance with the present invention.
The hollow plastic bottle of the present invention comprises: a hollow body of thermoplastic material having a generally cylindrical side wall, an upper end with a dispensing opening therein, and a lower supporting base with an inwardly extending central portion thereof, wherein said inwardly extending base includes a continuous outer supporting annular rim for supporting the bottle on a surface, a central portion, and a plurality of substantially uniform, continuous, uninterrupted, circumferential rings occupying substantially the entire space between the central portion and the outer supporting rim, said rings forming substantially continuous, uninterrupted, uniform circumferential, pyramidal ridges and adjacent depressions. The plastic bottle is desirably biaxially oriented and blow molded, and polyethylene terephthalate is a preferred material.
In a preferred embodiment, the hollow plastic bottle of the present invention comprises: a hollow body of thermoplastic material having a generally cylindrical side wall, an upper end with a dispensing opening therein, and a lower supporting base with an inwardly extending central portion having an outside surface thereof; wherein said outside surface of said inwardly extending base includes a continuous outer supporting annular rim for supporting the bottle on a surface; a central portion of said base; wherein the space between the central portion of the base and the outer supporting rim includes a plurality of substantially uniform, continuous, uninterrupted, circumferential rings forming substantially uniform, continuous, uninterrupted, circumferential, pyramidal ridges and adjacent depressions.
Desirably, the space between the central portion of the base and the outer supporting rim includes a plurality of additional substantially uniform, circumferential rings forming circumferential, pyramidal ridges and adjacent depressions, said additional rings having at least one substantially flat area thereon. The flat areas may be one, two or three or more separate flat areas and desirably include one of designations, symbols, at least one number, and at least one letter embossed thereon. The flat areas generally interrupt said additional rings. In the preferred embodiment, the flat areas contact at least three of said additional rings.
The uninterrupted rings and additional rings preferably occupy substantially the entire space between the central portion of the base and the outer rim. In a preferred embodiment, at least two of said uninterrupted rings are provided adjacent the central portion of the base and at least two of said uninterrupted rings are provided adjacent the annular rim, with said additional rings therebetween.
The plastic bottle of the present invention has improved strength properties so that the container may be effectively utilized for increased heat applications, as for example, pasteurization, without adverse effects. In addition, the container of the present invention is less susceptible to roll-out or bulging at the base, and has improved impact properties.
Further features and advantages of the present invention will appear hereinbelow.